1. Field of the Invention
The following description relates to a multiple input multiple output (MIMO) communication system using a codebook, and more particularly, to codebooks corresponding to respective reporting modes used by a transmitter and a receiver included in a MIMO communication system.
2. Description of the Related Art
A multiple input multiple output (MIMO) communication system may include a transmitter and at least one receiver. For example, the MIMO communication system may include a base station and at least one terminal. In a downlink, the base station may perform a functionality as the transmitter, and each of the at least one terminal may perform a functionality as the receiver.
The transmitter or the receiver operating in the MIMO communication system may include a plurality of antennas, and may transmit and receive data using the plurality of antennas. A wireless channel may be formed between each transmit antenna of the transmitter and each receive antenna of the receiver. The transmitter and the receiver may share information associated with the wireless channel, thereby achieving a high data rate.
In a closed-loop MIMO communication system, feedback information to be shared between the transmitter and the receiver may include a rank indicator indicating a preferred rank of the receiver, a precoding matrix indicator indicating a preferred precoding matrix, channel quality information indicating a quality of a wireless channel, and the like. The receiver may select one of matrices or vectors included in a codebook using a predefined codebook, and may feed back an index of the selected matrix or vector as the precoding matrix indicator.